Lithium ion batteries have a high energy density, power capacity, charge-discharge rate, endurance, and/or cycling lifetime. Typical lithium ion batteries include liquid electrolytes of lithium salts dissolved in solvents. The liquid electrolytes are often toxic, corrosive, and/or flammable.
Solid electrolytes based on solid lithium-rich antiperovskites having ionic conductivities (“σ”) of greater than 10−3 S/cm at room temperature and activation energies of 0.2-0.3 eV have been reported recently. The lithium-rich antiperovskite Li3OCl, for example, has been prepared by grinding together (i.e., ball-milling) LiOH and LiCl and then sintering the ball-milled mixture in a quartz tube at 300-360° C. under vacuum for several days to form Li3OCl. The melt that forms in the quartz tube is cooled to room temperature to afford Li3OCl having different microstructures. The procedure is repeated several times to ensure complete reaction and product uniformity. The prepared Li3OCl is used to prepare Li3OCl films on surfaces by pulsed laser deposition (“PLD”). A major disadvantage of this method is that the Li3OCl is unstable in air and reacts with the atmosphere even during transfer to the PLD apparatus.